The Gambling Commission's eagerly awaited prevalence study is expected to report that the number problem gamblers in Britain has doubled in the past eight years. The UK's Independent and Telegraph newspapers both said that around 600,000 people were now problem gamblers, while the more right wing Daily Mail put the figure closer to 800,000.

The report, carried out by research specialist NatCen, will be Gordon Brown's benchmark for new gambling policy and legislation, and is based on a study of more than 9,000 people.

The British Gambling Prevalence Study is also expected to say that the number of Britons who gamble has soared from 33million to 40 million. The findings match estimates from gambling experts and charities.